The external calibration or sizing of large-diameter tubular elements, such as longitudinally welded or so-called longitudinal-seam pipes and like large-diameter structures such as drums, tanks and the like, generally comprises a die or other structure through which the tubular element is drawn for imparting the desired external diameter thereto.
In U.S. Pat. No. 3,461,710, for example, a supporting outer ring is mounted upon a machine frame and is provided with a plurality of wedges which are fixed to the outer ring. These wedges are individually displaced by an array of cylinder arrangements (fluid-operated piston-and-cylinder assemblies) which are distributed around the periphery of the ring and are supported by the machine frame.
By actuating these cylinder arrangements, the support ring and the wedge mechanisms are displaced to adjust the tool segments which engage the tubular element and impart the desired diameter to the tube.
The support ring can be mounted in or guided in the machine frame as well. This system has been found to be expensive, difficult to manipulate and incapable of adjustment in all cases for the sizing or calibration of large-diameter tubular bodies.